The present invention generally relates to intravascular procedures, such as treating carotid arteries and percutaneous transluminal coronary angioplasty (PTCA), and particularly to an intravascular catheter which can be utilized in a rapid-exchange (RX) or over-the-wire (OTW) operating mode.
In typical PTCA procedures utilizing over-the-wire mode, a dilation catheter is advanced over a guide wire slidably disposed within an inner lumen of the dilation catheter into a patient""s coronary artery until the balloon on the distal extremity of the dilation catheter is properly positioned across the lesion to be dilated. Once properly positioned across the lesion, the flexible, relatively inelastic dilatation balloon on the catheter is inflated to a predetermined size with radiopaque liquid at relatively high pressures (e.g., generally 4-20 atmospheres) to dilate the stenosed region of the diseased artery. One or more inflations of the balloon may be required to complete the dilation of the stenosis. After the last dilation, the balloon is deflated so that the dilatation catheter can be removed from the dilated stenosis and so that blood flow can resume through the dilated artery.
One significant improvement in dilatation catheters has been the introduction of rapid-exchange type dilatation catheters. These catheters have a short guide wire receiving sleeve or inner lumen extending through the distal portion of the catheter which extend from a distal guide wire port in the distal end of the catheter to a proximal guide wire port spaced proximal to the proximal end of the dilatation balloon. The proximal guide wire port is usually located at least about 10 cm. and usually not more than about 50 cm. from the distal guide wire port. A slit is preferably provided in the catheter wall which extends from the second guide wire port, preferably to a location proximal to the proximal end of the inflatable balloon to aid in the removal of the catheter from a guide wire upon withdrawal of the catheter from the patient. The structure of the catheter allows for the rapid exchange of the catheter without the need for the use of an exchange wire or adding a guide wire extension to the proximal end of the guide wire. The design of this catheter has been widely praised by the medical profession and has met with much commercial success in the market place because of its unique design. The RX type dilation catheters of the assignee for the present invention, Advanced Cardiovascular Systems, Inc., have had a significant impact in the market for rapid-exchange type dilation catheters. Such products include dilatation catheters sold under the tradenamesxe2x80x94The Alpha, The Streak, and The Ellipse.
However, there is one significant inconvenience with the use of RX type dilatation catheter systems, namely, the inability to remove a guide wire already in place within a patient""s vasculature during an angioplasty procedure without losing access to the vascular location. There has been no convenient way in which to withdraw an in-place guide wire and then advance a replacement guide wire without losing access to the location of the distal end of the RX type dilatation catheter the short guide wire receiving inner lumen in the distal extremity of a RX type dilatation catheter. These instances occur when there is a need to replace an in-place guide wire with another guide wire having a different structure, e.g., an intermediate or standard wire with a core wire which extends to the distal tip of the guide wire. The need to withdraw an in-place guide wire also occurs when the distal tip of the in-place guide wire needs to be reshaped.
U.S. Pat. No. 5,807,355 (Ramzipoor et al.), which has been assigned to the present assignee, Advanced Cardiovascular Systems, Inc., describes an intravascular catheter with both RX and OTW operative modes. The Ramzipoor et al. patent is incorporated herein by reference. While this catheter provides for RX and OTW modes of operation, which is by choice of the operating physician, only one mode may be used at a time thus limiting the effective usefulness of the device. Additionally, the Ramzipoor dual mode catheter does not provide for a smooth RX guide wire exit port for used during RX modes. During such use, the RX guide wire will deform during passage through the expanded helical coil guide wire port. The need still exists therefore for a catheter which allows for simultaneous dual mode operation and which provides for a smooth exit notch. The present invention satisfies these and other needs.
This invention is directed to an elongated intravascular catheter which can be utilized in a rapid-exchange (RX) and/or an over-the-wire (OTW) mode of operation to perform an intravascular procedure, and particularly to a balloon dilatation catheter which can be used within the coronary arteries of a human patient during an angioplasty procedure.
The intravascular catheter of the invention generally comprises an elongated shaft with proximal and distal ends, a port in the distal end, a first lumen extending through the catheter from the port in the catheter distal end to a location spaced proximal to the proximal end of the balloon, and a second lumen extending through the catheter from the proximal end to the port in the distal end of the catheter. The catheter shaft has an elongated proximal section, an intermediate section, a relatively short distal section and a balloon or other means to perform an intravascular procedure on the distal section.
In the RX mode, the intravascular catheter can be advanced over an in-place guide wire within the first guide wire lumen while holding onto the proximal extremity of the guide wire extending out of the patient, until the distal end of the catheter is disposed within a desired location of the patient""s vascular system. The in-place guide wire is external of the catheter proximal to the opening in the intermediate shaft section of the catheter. In this manner, the in-place guide wire can be removed by pulling on the proximal extremity thereof which extends out the patient and a replacement guide wire can be introduced into the proximal end of the catheter shaft, advanced through the catheter shaft in the second guide wire lumen in the OTW mode and then out the port in the distal end of the catheter.
For coronary artery use, the opening in the intermediate shaft section is preferably spaced longitudinally at least 30 cm from the distal end of the catheter shaft to ensure that it remains within a guiding catheter when the distal shaft section extends out into the patient""s coronary artery.
In one embodiment, the distal shaft section of the catheter includes dual guide wire lumens, a first guide wire lumen entering the RX guide wire port in the intermediate shaft section, extending throughout the intermediate shaft section, the distal shaft section and then out the opening in the distal end of the catheter, and a second guide wire lumen extending throughout the entire catheter from the proximal shaft section to the distal shaft section and then out the port in the distal end of the catheter. The first guide wire lumen slidably receives an RX guide wire and the second guide wire lumen slidably receives an OTW guide wire.
In another embodiment of the invention, a y-section inner member having a slidable insert jacket provides a first (RX) guide wire lumen and a second (OTW) guide wire lumen of the proximal shaft section to communicate, forming a notch junction in the intermediate shaft section, wherein a single lumen, the distal section guide wire lumen, is formed which extends throughout the distal shaft section of the catheter and then out the port in the distal end of the catheter. The slidable insert jacket allows the physician to dictate the mode of operation. For the RX mode, the slidable insert jacket is pushed forward blocking off the second guide wire lumen at the notch junction and allowing the first guide wire lumen to be in fluid communication with the distal section guide wire lumen of the distal shaft section. For the OTW mode, the slidable insert jacket is slightly pulled back thus allowing the second guide wire lumen to be in fluid communication with the distal section guide wire lumen of the distal shaft section. Therefore, by a simple pull or push of the slidable insert jacket, the physician may choose either RX or OTW modes of operation.
In yet another embodiment, the proximal shaft section of the catheter comprises a lumen having a xe2x80x9cpeel-awayxe2x80x9d slit. The peel-away proximal shaft section serves both OTW and RX modes of operation. The guide wire lumen of the proximal shaft section has a slit which allows for the guide wire to be xe2x80x9cpeeled-awayxe2x80x9d and removed from the guide wire lumen, wherein the slit width is slightly smaller than the guide wire diameter thereby allowing the guide wire to remain within the lumen during the OTW mode of operation. The guide wire lumen slit, because of the deformable character of the material used, allows for the guide wire to be xe2x80x9cpeeled-awayxe2x80x9d or pulled out of the guide wire lumen via the guide wire lumen slit, thus allowing the RX mode of operation. The guide wire lumen slit runs throughout the proximal shaft section and ends in a location proximal to the distal shaft section at the intermediate shaft section. The intermediate shaft section is reinforced with a peel-away strain relief which ensures that the guide wire lumen slit will not propagate distally into the distal shaft section of the catheter.
Other features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.